Acclaimed Flop: Critics did like the movie, but it's considered a box-office failure for Dreamworks since the actual revenue did not meet the cost of production and advertisement. In fact, the losses forced Dreamworks to lay off over three hundred workers!
Almost at the start. This was the first in-house movie since Sinbad: Legend of the Seven Seas that lost the company money (Flushed Away from Aardman also bombed, but DWA distributed that one only, and the results ended their relationship with Aardman). DreamWorks was forced to lay off over 300 employees just to compensate for it. Since then, DreamWorks has come out to the public revealing that they need Cash Cow Franchise to stay afloat, and given that this movie flopped, chances of a sequel are not likely.
More importantly, Rise of the Guardians was the first in a chain of all but three films that were either not critically successful enough or not commercially successful enough due to high budgets and marketing costs combined (The Croods, How to Train Your Dragon, and Kung Fu Panda 3 were those three films that were major hits in both fields during the chain.) The last movie in the chain so far, Home, was a great financial success, but was critically disliked, and the chain eventually claimed the careers of an additional 500+ DWA employees and three critical DreamWorks Animation head honchos: Chief Creative Officer Bill Damaschke (he resigned in 2015 after having been with the studio since their doors opened), the 2014 Chief Operating Officer Mark Zoradi (another Walt Disney Co. veteran for 3 decades, he joined DWA in the middle of 2014, but the financial troubles got his job in only months) and finally, DreamWorks co-founder/Chief Executive Officer/Disney veteran Jeffrey Katzenberg himself; Katzenberg agreed to sell DWA to Comcast/Universal in 2016, but the agreement forces him to retire from the Shrek Shack (he will remain attached as the boss of DreamWorks New Media, which is an online company overseeing Awesomeness TV.)
Dawson Casting: Voice casting anyway, maybe. Jack Frost looks like a teenager and his voice is a lot more mature than you'd expect from a teenage boy, though not to the point of being unbelievable.
Also note that in his flashback scene, Jack's voice was slightly more high-pitched.
Doing It for the Art: The directors' commentary consists almost entirely of the directors geeking out over how beautiful the movie is and giving a Shout-Out to the designers and animators who made it so.
Fake Nationality: Alec Baldwin gives North a booming Russian accent, and the very American Tooth Fairy is voiced by the decidedly Australian Isla Fisher. Her compatriot Hugh Jackman (for once) gets to avert this trope in a non-Australian production as Bunnymund.
What Could Have Been: Leonardo DiCaprio was originally going to voice Jack Frost, but he dropped out supposedly because of schedule conflicts. His voice is somewhat higher and would've fit Jack's apparent age more than Chris Pine's. (Leonardo had previously played a character named Jack as well.)note Which would have been one hell of an Actor Allusion as both versions of Jack involve death by drowning in freezing cold water!
Early casting reports also reported Christopher Lee as a choice for the voice of North.
This is why Bunnymund is such a different character- he was going to be closer to the books until they brought Hugh Jackman in as his voice; which is where he then immediately became the warrior type he is in the movie.
Guillermo del Toro's suggestion for the story was to have Jamie be the Audience Surrogate. And at least one early version had the climax take a darker turn in which Pitch uses his Nightmare Galleon to harpoon the Moon to create an eclipse to gather his dark forces under for an assault against the Man in the Moon himself.
And as shown in the Art Book of Rise of the Guardians there are several illustrations of Sandy's Sandship, which flies around the world constantly remaining within the twilight time zone region to help Sandy spread dreams. The ship took many forms all revolving around an ocean theme with the ship even resembling a turtle and whale at one point. The ship was to be included in battle against Pitch, where the Nightmares overpowering the ship and eventually consuming it, with Jack reaching out for Sandy's hand before he fades as well.
Some more early concept art for the film reveals that initial designs for Pitch were much more demonic and nightmarish than the film's version of him, which isn't all that different from the books. The concept art also reveals a scene in which Pitch joins with his nightmare sand and becomes as tall as a skyscraper, raining nightmares down upon the world, with Jack clinging on for dear life and looking down at the nightmare sand entering peoples' homes.
There was almost a Jack Frost doll made by Mattel.
There were early storyboards depicting a very different plot of the story, in which Toothiana meets Jack first, she promises to get his teeth back, Bunnymund is still a professor-rabbit, etc. The storyboard had Toothiana being kidnapped numerous times and seemed to lead more to the Tooth x Jack Ship Tease.